Automatic cut-out valve for internal combustion engines



Dec. 17, 1935. w -r ms 2,624,193 Y AUTOMATIC CUT-OUT VALVEFOR INTERNAII COMBUSTION ENGINES Filed July 22, 1933 linventor' 7 4? 7). Wm,

Gttornegs Patented Dec. 17, 1935 PATENT OFFICE AUTOMATIC CUT-OUT VALVE FOR INTER NAL COIH'BUSTION ENGINES Lucius D. Watkins, Milwaukee, Wis., assignor to Outboard Motors Corporation,

Milwaukee,

Wis., a corporation of Michigan Application July 22, 1933, Serial No. 681,765

r 8 Claims.

This invention relates to improvements in automatic cut-out valves for internal combustion engines and, more particularly, to an outboard motor organization in which the exhaust gases are discharged'under water during normal operation of the device, but are automatically bypassed directly into the open air under control of the engine and its cooling system.

It is a device that'has particular utility for marine purposes where it is common practice to exhaust under water. In starting, and until the device gains speed through the water, an underwater exhaust ofiers a certain amount of back pressure. Hence, it is a primary object of the invention to provide a novel and simple automatic exhaust valve controlled by heat developed in the engine for relieving against back pressure.

In the drawing:

Figure 1 shows an outboard motor in side elevation with a portion of the exhaust expansion chamber broken away to expose the'application thereto of an automatic exhaust valve embodying the present invention.

Flgure2 is a rear elevation of the expansion chamber on an enlarged scale, a portion thereof being broken away to show the valve.

Figure 3 is a view similar to Figure 2, showing a modified embodiment of the invention.

Figure 4 is a longitudinal section through the expansion chamber illustrating the application of the automatic exhaust valve thereto.

Like parts are identified by the same rei'erence characters throughout theseveral views.

The outboard motor illustrated'is of a conventional design in which the transom bracket 5 carries a shaft housing 6 which connects the lower unit 1 with the engine 8. The exhaust gases from the engine are delivered into the expansion chamber 9 from which they pass downwardly through exhaust pipe Hi to an exhaust port at H in the lower unit, which is so formed that the relative motion of the device with respect to the water will aspirate the. exhaust gases from the apparatus when the device is in normal use.

When the engine 8 is being started, with the apparatus at rest in the water, the back pressure developed in the expansion chamber 9 and exhaust pipe Ill by the water sealing the mouth of outlet I I, may be somewhat high. The same condition may exist when the motor is idling very slowly. It is desirable, therefore, to provide one or more release ports I! from which the exhaust gases may escape from the expansion chamber 9 under such circumstances. In order to close these ports when the engine and the outboard motor are operating normally, the present invention contemplates the use of a thermostatic, bimetallic valve IB which may comprise a disk, as shown in Figs. 1, 2, and 4, or may comprise a bimetallic strip, as shown at It in Fig. 3.

When the bimetallic valve I6 is cooled, it takes the form shown at Fig. 1 and the ports ii are fully exposed for the escape of. exhaust gases. When the bimetallic valve becomes very warm, as it does when the engine is in normal operation, the expansion of the inner ply oi its component material causes the valve to assume the form shown in Fig. 4. In this position of the valve the openings l5 are closed and exhaust discharge must take place through the submerged outlet l l. The valve shown in Fig. 3, operates in the same manner as that above described.

The organization of the parts may be such that the initial heat of the exhaust gases will close the valve as soon as the engine starts. Preferably, however, the valve is so made that it will not be closed immediately but will only be closed when the engine reaches a substantially increased temperature. In order to keep the valve open when the engine is merely idling, I may cool the expansion chamber, which, being usually made of aluminum, is ordinarily highly conductive of heat. The conventional outboard motor as illustrated, has a water inlet at ll in its lower unit I. The water is acted upon by pump It and delivered through pipe l9 to the engine Jacket. From the jacket, pipe 20 leads to an expansion chamber or muiiier jacket 2| from which the water overflows and is discharged through pipe 22 (see Fig. 4). As an alternative arrangement, the pipe 20 may discharge just above the back of the expansion chamber at 23, as shown in Fig. 1. I

When the engine is idling, the pump it will not drive the water with any particular force and it will trickle from the discharge port 23 of pipe 20, thus directly cooling the outside of the expansion chamber and preventing valve it from becoming heated sufllciently to close the ports I5. When the engine is in normal operation, the pump It will circulate the water with sumcient rapidity so that it will flow in a stream or Jet from the discharge port 23 without contacting the expansion chamber.

In any case, it is the heat of the exhaust striking the bimetallic valve member II which eventually causes the operation thereoi. The various cooling arrangements disclosed merely defer that operation under certain circumstances, and may cause the automatic valve to open sooner than it might otherwise do, after it has once been closed.

I claim:

1. The combination, in a marine motor exhaust system with an exhaust passage provided with an atmospheric discharge port and a secondary underwater discharge passage, of means for thermostatically employing the heat of exhaust in said passage to close said port and force the exhaust fluid to discharge through said passage.

2. The combination with an internal combustion engine having an exhaust pipe provided with an aperture, of means thermostatically controlling said aperture, and engine operated means for regulating the temperature of said controlling means. I

3. The combination with an internal combustion engine having an exhaust passage provided with a cut-out aperture, of a thermostatic valve controlling said aperture, and engine operated water circulating means for regulating the temperature of said thermostatic valve.

4. The combination with an engine having a cooling jacket and water circulating means, of an exhaust gas conduit provided with a cut-out port, thermostatic valve means controlling said port, and means for discharging cooling water from the jacket of said enginein heat receiving proximity to said thermostatic valve means, whereby to temper the operation thereof.

5. The combination with a marine motor comprising an engine having an exhaust passage and an under-water exhaust delivery port, said passage being provided with a cut-out opening,

of means for thermostatically controlling the said opening, and engine driven means for circulating water in heat transferring relation to said thermostatic means to temper the operation thereof.

' 6. An outboard motor comprising the combination with an engine having an exhaust discharge pipe terminating below the water line and provided above the water line with'a cut-out port, of a bimetallic valve applied to said-port and adapted when heated to eifect the closure thereof, and when cooled to open said port whereby said port will be automatically controlled in accordance with motor conditions to which the exhaust temperature responds. I

7. In an outboard motor having an exhaust system and a water cooling system, the combi- 5 nation of an exhaust chamber having a wall providing a free exhaust discharge port, means controlling said port including a thermostat adjacent said wall and positioned to be heated by exhaust products in said chamber, and a disl0 charge nozzle for water from said cooling system disposed above said wall at such a point that water flowing therefrom under substantial pressure developed by relatively high speed operation ofsaid motor will be projected beyond said wall, 15 but said point being also so chosen that water flowing from said nozzle under light pressure developed by relatively slow speed operation of said motor will flow downwardly in contact with,said wall for rapidly cooling said wall and thermo- 20 stat to cause prompt operation thereof upon changes of speed in said motor.

8. The combination with a mobile motor comprising an engine, a propeller operatively connected to be driven by the engine for the pro- 25 pulsion thereof in general proportion to the work output of the engine, and an exhaust passage leading from the engine to a point adjacent the propeller and rearwardly directed withreference to the direction of propeller thrust, whereby ex- 30 haust gases are aspirated therefrom by the fluid in which the propeller operates to a degree which is in general proportion to the rate of propeller operation, a cut-out port openingdirectly from said passage adjacent said engine, and thermostatic valve means controlling said port and operatively organized for the opening thereof at low temperatures and the closing thereof at high temperatures, whereby said port will automatically be opened below a predetermined approximate degree of aspiration from said exhaust passage and closed abovetsaid approximate degree of aspiration,

LUCIUS D. WATKINS. 

